The invention discloses a method for preparing palladium nitrate, which comprises the following steps of: putting high-purity metal palladium or sponge palladium into a container, slowly adding concentrated nitric acid and hydrogen peroxide by batches, and heating for dissolution; cooling and filtering the solution, heating for evaporating and concentrating until solid-state crystal grains appear on liquid surface, and cooling for crystallization; and washing the obtained crystals with cold water, performing vacuum drying, and grinding into powder to obtain the palladium nitrate product. Compared with the prior art, the method has the advantages that: the concentrated nitric acid and the hydrogen peroxide are added slowly by batches in the dissolving process, the palladium dissolving capacity is improved, the reaction speed is improved, the using amount of the concentrated nitric acid is reduced, steps are simple, the efficiency is high, the production cost is low, and the palladium nitrate contains crystal water, has homogenous property and the purity close to 100 percent, and is a high-quality palladium nitrate product.